The invention relates to an arrangement for reading out an information signal from a magnetic record carrier, comprising:
(a) a read head having a magneto-resistive element with a first terminal connected to a first point of constant potential, and with a second terminal; PA1 (b) a first bias-current generator for supplying a bias-current; and PA1 (c) a first amplifier circuit having (i) an output terminal for supplying the information signal, (ii) a first terminal coupled to the first bias-current generator and to the output terminal, (iii) a second terminal coupled to the second terminal of the magneto-resistive element so as to form a series arrangement of the first bias-current generator, the first amplifier circuit and the magneto-resistive element between a second point of constant potential and the first point of constant potential, (iv) a first transistor, (iv) a first feedback circuit, (vii) a first load impedance and (vii) a first capacitor element, a first main flow terminal of the first transistor being connected to the second terminal of the first amplifier circuit, a second main flow terminal of the first transistor being coupled to the first terminal of the first amplifier circuit, a control terminal of the first transistor being coupled to the output terminal of the first amplifier circuit via the first feedback circuit, and the first load impedance being coupled between the output terminal of the first amplifier circuit and a reference voltage terminal. PA1 (d) a second bias-current generator for supplying a bias-current; and PA1 (e) a second amplifier circuit having (i) an output terminal, PA1 (ii) a first terminal coupled to the second bias-current generator and to the output terminal, (iii) a second terminal coupled to the first point of constant potential, optionally via a further magneto-resistive element, so as to form a series arrangement of the second bias-current generator, the second amplifier circuit and further magneto-resistive element between the second point of constant potential and the first point of constant potential, (iv) a second transistor, (v) a second feedback circuit, (vi) a second load impedance and (vii) a second capacitor element, a first main flow terminal of the second transistor being connected to the second terminal of the second amplifier circuit, a second main flow terminal of the second transistor being coupled to the first terminal of the second amplifier circuit, a control terminal of the second transistor being coupled to the output terminal of the second amplifier circuit via the second feedback circuit, the second load impedance being coupled between the output terminal of the second amplifier circuit and a reference voltage terminal. Furthermore, the control terminal of the second transistor is coupled to the second terminal of the first amplifier circuit via the second capacitor element, and the control terminal of the first transistor is coupled to the second terminal of the second amplifier circuit via the first capacitor element.
Such an arrangement is known from U.S. Pat. No. 5,270,882. In this known arrangement, current biasing and current sensing of tile magneto-resistive element is combined, thereby providing a low-noise amplification.